In recent years, ocean current power generation devices that generate power using energy from seawater flows such as ocean currents and tidal currents and the like have been developed.
Typically, ocean current power generation devices have a turbine that is located underwater and is rotated by a flow of seawater, and use the rotation of this turbine to drive a power generator so as to generate power. Such turbines include horizontal axis turbines in which the axis of rotation is parallel (i.e., horizontal) to the flow of seawater, and vertical axis turbines in which the axis of rotation is perpendicular to the flow of seawater.
A semi-submersible ocean current power generation device (see Patent document 1) has been developed as an actual ocean current power generation device. This semi-submersible ocean current power generation device is provided with three hollow columns that, when seen in plan view, are placed at the respective apex points of a triangle, and with propeller water wheels (i.e., horizontal axis turbines) that are provided on each one of these hollow columns and are rotated by the flow of seawater. The ocean current power generation device is driven by this rotation of the propeller water wheels so as to generate power.